• Proceedings of the KIEE Conference
• /
• 1997.11a
• /
• pp.314-316
• /
• 1997

We have studied the epitaxial growth and electrical properties of $Si_{0.8}Ge_{0.2}$, films on Si substrates at $550^{\circ}C$ by LPCVD. In a low $PH_3$, partial pressure region such as below 1.25 mPa, the phosphorus doping concentration increased proportionally with increasing $PH_3$ partial pressure while the deposition rate and the Ge fraction x were constant. In a higher $PH_3$ partial pressure region, the phosphorus doping concentration and the deposition rate decreased, while the Ge fraction slightly increased. The dependence of P incorporation rate on the $PH_3$ partial pressure was similar to the phosphorus doping concentration. According to test results, it suggests that high surface coverage of phosphorus atoms suppress both the $SiH_4$ adsorption/reaction and the $GeH_4$ adsorption/reaction on the surfaces, and the effect is more stronger on $SiH_4$ than on $GeH_4$. In a higher $PH_3$ partial pressure region, the deposition is largely controlled by surface coverage effect of phosphorus atoms.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.48 no.4
• /
• pp.247-252
• /
• 1999

In this paper, in order to investigate availability of the OW-PD measurement method which has been proposed as an alternative of AC-PD measurement method to an after laying test and/or diagnosis for the power cable system, partial discharges owing to the needle-type defect integrated into the cable have been measured using AC and OW(Oscillating Wave) voltages. In the AC-PD measurement, the magnitude, phase and pulse number of partial discharges have been changed with the duration of voltage application, which can be analyzed through the relation with the process of the electrical tree initiation and propagation. In addition, the characteristics of partial discharges using OW voltage are appeared to be similar to those in case of AC-PD measurement and to be different with the shapes of electrical tree. From these results, it is concluded that the OW-PD measurement method is available to the tests for the cable system.

• Fire Science and Engineering
• /
• v.20 no.2 s.62
• /
• pp.72-79
• /
• 2006

The objective of this study is to analyze the smoke extraction efficiency using by the partial extraction system with CFD simulation for case of tunnel fire. The Comparison of CFD results with the preceding scaled model test results, it is equal to the smoke extraction efficiency and smoke stratification in tunnel by the partial smoke extraction system (distributed damper). It shows that the smoke extraction efficiency is increased about 7% by the distributed damper which is opened near fire, compare with the distributed damper which is all opened. The case of the fire occurs on a traffic jam in a tunnel, it is proposed that the operating method of partial smoke extraction system for the escaping passengers.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.9
• /
• pp.1784-1789
• /
• 2009

This paper describes the measurement technology of the dissolved hydrogen gas due to partial discharge in oil using gas sensor. For higher resolution and less error in measurement of the dissolved hydrogen gas in oil, the sensor outputs with ambient temperature which affect the sensor output characteristics should be considered. The sensor output trends with ambient temperature and the properties of the dissolved hydrogen gas in oil with partial discharge characteristic were analyzed through the test results. It was indicated that the sensor peak and the base voltage with measuring time were affected by ambient temperature and the measurement errors of the sensor output by temperature were reduced by using the difference between the peak and the base voltage rather than just the peak voltage. In addition, the hydrogen gas sensor outputs were increased with the increase of partial discharge energy.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.23 no.1
• /
• pp.169-181
• /
• 2010

Objective : The purpose of this study was to investigate the effects of Combination therapy with Gwakhyangjeonggisangamibang and Sojangjeonggyeok on patients with verucca plana. Methods : Sixty-five patients(male 19, female 46) with verruca plana were treated with Gwakhyangjeonggisangamibang and Sojangjeonggyeok for at least 3 months. After treatment, a clearance rate was divided into 4 scales such as; complete clearance / partial clearance-good / partial clearance-poor / no change. Statistical analysis was performed by using Independent-sample t-test. Results : Mean age of patients was 30.3 and mean period of disease duration was 64.6 months. Fifty-eight patients(73.8%) showed complete clearance, nine(13.8%) partial clearance-good, and eight(12.3%) partial clearance-poor. Complete clearance group(CC group) was statistically younger than failure group and disease duration of CC group was shorter than failure group. Although treatment period of failure group was statistically longer than CC group and dosage(貼) of herbal medicine of failure group was more than CC group, failure group showed partial clearance. Conclusion : This data demonstrates that combination therapy with Gwakhyangjeonggisangamibang and Sojangjeonggyeok could be an effective and safe treatment for the verucca plana.

• The Journal of the Korean dental association
• /
• v.57 no.1
• /
• pp.18-25
• /
• 2018

Objectives: This study aimed to compare the postoperative pain and clinical performance after partial pulpotomy by using ProRoot MTA and Endocem MTA. Materials and Methods: Twenty-eight teeth requiring partial pulpotomy due to deep dental caries or traumatic injury were included in this study. After 2mm removal of exposed pulp and bleeding control, the ProRoot MTA or Endocem MTA was randomly adjusted to the exposed site. 1, 2, 4, and 12 weeks after the final restoration, the patients were recalled to check the postoperative pain or another unfavorable signs. Pearson's chi-square test was used for statistical analysis to evaluate any differences among tested materials. Results: 3 of 28 teeth showed postoperative pain and cold positive during follow-up period (10.7%). There were no statistically differences in pain occurrence between two tested materials (P > 0.05). Conclusions: In the limitations of this study, partial pulpotomy by using Endocem MTA showed the advantages of short setting time and lower postoperative pain incidence, allowing one visit treatment.

• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.10 no.1
• /
• pp.15-22
• /
• 2012

Purpose : We investigated the effects of the combined use of FES and over ground walking with partial body-weight support (PBWS) on walking function and balance control in people with chronic strokes. Methods : Twenty-seven people who were ambulatory after chronic strokes were evaluated. The exercise's intervention consisted of the combined use of FES and over ground walking with PBWS and general exercise groups. The FES + PBWS group and general exercise group consisted on a-20-minute session per day, 3 times a week during a 4 week period. The evaluation was carried out before, after, and two weeks after the exercise intervention. Outcome measures were a 6 Minute Walk Test, 6-Meter walk Test, Timed Up and Go Test, and a Balance Test, measured before and after the exercise interventions at a-2 week follow up. Results : The endurance was significantly increased in both the FES+PBWS group and general exercise group (p<0.05). Significant increase on the gait velocity was observed in both the FES+PBWS group and general exercise group (p<0.05). The TUG was significantly different in both the FES + PBWS group and general exercise group (p<0.05). However there were no differences in both the between-group & interaction. The stability index was significantly different in both the FES + PBWS group and general exercise group (p<0.05). Conclusion : In conclusion, the combined use of FES and over ground walking with PBWS led to an improvement in walking function and balance control. Thus, it is possible to combine the use of FES and over ground walking with PBWS for physical therapy intervention to improve walking function and balance control. It is suggested to apply this intervention in the clinical field.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.6
• /
• pp.1769-1776
• /
• 2016

For on-line partial discharge (PD) monitoring of rotating machines, a novel sensor is proposed, which can be installed on the power lead inside the terminal box of the machine. The sensor has been designed to have high capacitance, and minimal reflection of measured pulses. As a sensitivity of the sensor, transfer impedance $Z_t$ has been measured and compared to conventional coupler-type sensors. A simple method is presented for measuring $Z_t$ of coupler sensors, using a vector network analyzer and a practical lead-cable of rotating machine. Through this method, it became possible to measure the $Z_t$ of coupler sensors including the installation environment of them. The $Z_t$ of the proposed sensor is higher than that of same sized other conventional couplers at frequencies between 30 and 92 MHz. Another sensitivity test has been performed using a PD calibrator as a test pulse source. The proposed sensor has higher measured peak voltage than the conventional coupler type sensors when the same charges were input.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.11 no.4
• /
• pp.10-18
• /
• 2007

A tested micro axial-type turbine consists of two stages and its mean radius of rotor flow passage is 8.4 mm. This turbine could be applied to a driver of micro power system, and its rotational speed in the unloaded state reaches to 100,000 RPM. The performance of this system is sensitive depending on the blade angles of the rotor and stator because it is operated in a low partial admission rate, so a performance test is conducted through measuring the specific output power and the net specific output torque with various blade angles on the nozzle, stator and rotor. The experimental results show that the net specific output torque is varied by 15% by changing the rotor blade angle, and the optimal incidence angle is about $10.3^{\circ}$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.109-109
• /
• 2010

On-line partial discharge(PD) diagnostic system is the most prominent systems to diagnose insulation condition for the high voltage rotating machines. Partial discharge measuring system(PDMS) series with ceramic coupler(PD detecting sensor) installed hydro generator and high voltage motor have been measured the PD data for many years. The trend of PD magnitude in the on-line PD system increased for some machines. These machines showed a same result in the conventional off-line PD test and PD magnitude decreased after stator winding insulation cleaning. This case study show that PDMS has been proved to be good results by comparing PD magnitude with on-line and off-line PD test and it is important to plan the maintenance project for the hydro generator stator winding because PD value was decreased after insulation cleaning.